\begin{figure}[h]
  \centering
  \caption{Exemplo de grafo arco-circular próprio mas não arco-circular
    unitário e sua representação por arcos\label{fig:dif}}
  \begin{tikzpicture}[scale=0.7]
    \coordinate (A) at (0,0);
    \coordinate (B) at (1,1);
    \coordinate (C) at (2,2);
    \coordinate (D) at (3,1);
    \coordinate (E) at (4,0);
    \coordinate (F) at (3,-1);
    \coordinate (G) at (2,-2);
    \coordinate (H) at (1,-1);
    \begin{scope}[thick]
      %\draw (0.30901699437, 0.95105651629) .. controls (-1.3,1.6)
      %and (-1.6,0.7) .. (-0.80901699437, -0.58778525229);
      \draw (A) -- (B) -- (C) -- (D) -- (E) -- (F) -- (G) -- (H) -- (A);
      \draw (B) -- (D) -- (F) -- (H) -- (B);
      \filldraw[] (A) circle(3pt);
      \filldraw[] (B) circle(3pt);
      \filldraw[] (C) circle(3pt);
      \filldraw[] (E) circle(3pt);
      \filldraw[] (D) circle(3pt);
      \filldraw[] (F) circle(3pt);
      \filldraw[] (G) circle(3pt);
      \filldraw[] (H) circle(3pt);
    \end{scope}
    \draw[dotted] (8,0) circle (1.5);
    \draw[dotted] (5.5,0) -- (10.5,0);
    \draw[dotted] (8,2.5) -- (8,-2.5);
    \draw[dotted] (5.5,2.5) -- (10.5, -2.5);
    \draw[dotted] (5.5,-2.5) -- (10.5, 2.5);
    \draw[thick] (9.7,0) arc (0:90:1.7);
    \draw[thick] (8,1.9) arc (90:180:1.9);
    \draw[thick] (6.3,0) arc (180:270:1.7);
    \draw[thick] (8,-1.9) arc (270:360:1.9);

    \draw[thick] (9.484,1.4849) arc (45:135:2.1);
    \draw[thick] (6.515, -1.4849) arc (225:315:2.1);
    \draw[thick] (6.3913,1.3498) arc (140:220:2.1);
    \draw[thick] (9.6086, -1.3498) arc (320:400:2.1);

  \end{tikzpicture}
  \begin{tikzpicture}
    %\clip (-1,-3) rectangle (5, 1.5);
  \end{tikzpicture}
  \floatsrc{Elaborado pelo autor}
\end{figure}