\begin{tikzpicture}[node/.style={circle, thick, draw, inner sep=1pt}]
\node[node] (v1) {v1};
\node[node, right= of v1] (v2) {v2};
\node[node, below left=of v1] (v3) {v3};
\node[node, below right=of v2] (v4) {v4};
\node[node, below left=of v4] (v5) {v5};

\draw[edge] (v1) -- (v2);
\draw[edge] (v1) -- (v5);
\draw[edge] (v2) -- (v3);
\draw[edge] (v2) -- (v5);
\draw[edge] (v3) -- (v4);
\draw[edge] (v3) -- (v5);
\draw[edge] (v4) -- (v5);
\end{tikzpicture}