\begin{tikzpicture}
                \tikzset{
                  arrowMe/.style={postaction=decorate,
                    decoration={markings, mark=at position .6 with {\arrow[very thick]{#1}}
                    } }}
                \def\r{1.7}
                \tkzDefPoint(0,0){o}
                \tkzDefPoint(0:\r){v1}\tkzDefPoint(60:\r){v2}\tkzDefPoint(120:\r){v3}\tkzDefPoint(180:\r){v4}\tkzDefPoint(240:\r){v5}\tkzDefPoint(300:\r){v6}
                \draw[arrowMe=stealth](v2)--node[right]{\(b\)}(v1);
                \draw[arrowMe=stealth](v3)--node[above=2pt]{\(a\)}(v2);
                \draw[arrowMe=stealth](v4)--node[left]{\(c\)}(v3);
                \draw[arrowMe=stealth](v5)--node[left]{\(c\)}(v4);
                \draw[arrowMe=stealth](v5)--node[below]{\(b\)}(v6); 
                \draw[arrowMe=stealth](v6)--node[right]{\(a\)}(v1);
                \draw (0,-2.3) node{(a)};
                \tkzDrawPoints(v1,v2,v3,v4,v5,v6)
                  \begin{scope}[xshift=5cm]
                  \def\r{1.7}
                  \tkzDefPoint(0,0){o}
                  \tkzDefPoint(22.5:\r){v1}\tkzDefPoint(67.5:\r){v2}\tkzDefPoint(112.5:\r){v3}\tkzDefPoint(157.5:\r){v4}\tkzDefPoint(202.5:\r){v5}\tkzDefPoint(247.5:\r){v6}\tkzDefPoint(292.5:\r){v7}\tkzDefPoint(337.5:\r){v8}
                  \draw[arrowMe=stealth](v2)--node[above]{\(b\)}(v1);
                  \draw[arrowMe=stealth](v2)--node[above]{\(a\)}(v3);
                  \draw[arrowMe=stealth](v3)--node[above]{\(b\)}(v4);
                  \draw[arrowMe=stealth](v4)--node[left]{\(d\)}(v5);
                  \draw[arrowMe=stealth](v6)--node[left]{\(c\)}(v5); 
                  \draw[arrowMe=stealth](v7)--node[below]{\(a\)}(v6);
                  \draw[arrowMe=stealth](v8)--node[right]{\(d\)}(v7);
                  \draw[arrowMe=stealth](v8)--node[right]{\(c\)}(v1);
                  \tkzDrawPoints(v1,v2,v3,v4,v5,v6,v7,v8)
                  \draw (0,-2.3) node{(b)};
                  \end{scope}
                  \begin{scope}[yshift=-5cm]
                  \def\r{1.7}
                  \tkzDefPoint(0,0){o}
                  \tkzDefPoint(22.5:\r){v1}\tkzDefPoint(67.5:\r){v2}\tkzDefPoint(112.5:\r){v3}\tkzDefPoint(157.5:\r){v4}\tkzDefPoint(202.5:\r){v5}\tkzDefPoint(247.5:\r){v6}\tkzDefPoint(292.5:\r){v7}\tkzDefPoint(337.5:\r){v8}
                  \draw[arrowMe=stealth](v2)--node[above]{\(b\)}(v1);
                  \draw[arrowMe=stealth](v3)--node[above]{\(a\)}(v2);
                  \draw[arrowMe=stealth](v3)--node[above]{\(d\)}(v4);
                  \draw[arrowMe=stealth](v5)--node[left]{\(c\)}(v4);
                  \draw[arrowMe=stealth](v5)--node[left]{\(c\)}(v6); 
                  \draw[arrowMe=stealth](v6)--node[below]{\(d\)}(v7);
                  \draw[arrowMe=stealth](v7)--node[right]{\(b\)}(v8);
                  \draw[arrowMe=stealth](v1)--node[right]{\(a\)}(v8);
                  \tkzDrawPoints(v1,v2,v3,v4,v5,v6,v7,v8)
                  \draw (0,-2.3) node{(c)};
                  \end{scope}
                  \begin{scope}[xshift=5cm,yshift=-5cm]
                  \def\r{1.7}
                  \tkzDefPoint(0,0){o}
                  \tkzDefPoint(0:\r){v1}\tkzDefPoint(36:\r){v2}\tkzDefPoint(72:\r){v3}\tkzDefPoint(108:\r){v4}\tkzDefPoint(144:\r){v5}\tkzDefPoint(180:\r){v6}\tkzDefPoint(216:\r){v7}\tkzDefPoint(252:\r){v8}
                  \tkzDefPoint(288:\r){v9}\tkzDefPoint(324:\r){v10}
                  \draw[arrowMe=stealth](v2)--node[right]{\(b\)}(v1);
                  \draw[arrowMe=stealth](v2)--node[above]{\(c\)}(v3);
                  \draw[arrowMe=stealth](v4)--node[above]{\(d\)}(v3);
                  \draw[arrowMe=stealth](v4)--node[above]{\(e\)}(v5);
                  \draw[arrowMe=stealth](v5)--node[left]{\(d\)}(v6); 
                  \draw[arrowMe=stealth](v6)--node[left]{\(c\)}(v7);
                  \draw[arrowMe=stealth](v7)--node[below]{\(e\)}(v8);
                  \draw[arrowMe=stealth](v8)--node[below]{\(a\)}(v9);
                  \draw[arrowMe=stealth](v9)--node[below]{\(b\)}(v10);
                  \draw[arrowMe=stealth](v1)--node[right]{\(a\)}(v10);    
                  \tkzDrawPoints(v1,v2,v3,v4,v5,v6,v7,v8,v9,v10)
                  \draw (0,-2.3) node{(d)};
                  \end{scope}
\end{tikzpicture}