\def\n{6}
\def\radius{2cm}

\begin{tikzpicture}[scale=.8]
     \begin{scope}
        \foreach \i in {1,...,\n} 
            \node[draw, small vertex] (v-\i) at ({-360/\n * (\i)}:\radius) {};
            
        \foreach \u/\v in {1/2,2/3,3/4,4/5,5/6,6/1} \draw[-, thick] (v-\u) edge (v-\v);
    \end{scope}
    \begin{scope}[xshift=3*\radius]
        \foreach \i in {1,...,\n} 
            \node[draw, small vertex] (v-\i) at ({-360/\n * (\i)}:\radius) {};
            
        \foreach \u/\v in {1/2,2/3,3/4,4/5,5/6,6/1} \draw[-] (v-\u) edge (v-\v);
        \foreach \u/\v in {2/6,6/3,3/5} \draw[-, thick] (v-\u) edge (v-\v);
    \end{scope}
    \begin{scope}[xshift=6*\radius]
        \foreach \i in {1,...,\n} 
            \node[draw, small vertex] (v-\i) at ({-360/\n * (\i)}:\radius) {};
            
        \foreach \u/\v in {1/2,2/3,3/4,4/5,5/6,6/1} \draw[-] (v-\u) edge (v-\v);
        \foreach \u/\v in {2/6,6/3,3/5} \draw[-] (v-\u) edge (v-\v);

        \draw[-, thick] (v-1) edge[bend left=60, out looseness=2.3] (v-3);
        \draw[-, thick] (v-1) edge[bend right=100, out looseness=4] (v-4);
        \draw[-, thick] (v-1) edge[bend right=60, out looseness=2.3] (v-5);
    \end{scope}
\end{tikzpicture}