\begin{tikzpicture}[]
\node[](0){G};
\path[->](0)edge[loop above]node{$g_1$}();
\foreach \looseness/\label [count=\n] in {10/$g_2$,15/$g_3$,20/$g_4$,27/$\cdots$}
	\path [->] (0) edge [
      loop above,
      every loop/.append style={
          looseness=\looseness,
          in=60-0.8*\looseness,
          out=120+0.8*\looseness
    }] node {\label} ();
\end{tikzpicture}