\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\def\R{3cm} % defined radius of circle
\draw (0,0) circle[radius=\R];
\draw (0,0) -- (60:\R) (0,0) -- (120:\R) (0,0) -- (180:\R) (0,0) -- (240:\R) (0,0) -- (300:\R) (0,0) -- (360:\R);
\node at (30:\R/2) {\(\{A,B,C\}\)};
\node at (90:\R/2) {\(\{A,B,C\}\)};
\end{tikzpicture}
\end{document}