Most methods for generating Euler diagrams describe the detection of the general structure of the final draw as the first and most important step. This information is often depicted using a graph, where nodes are regions to be represented and edges show adjacency relations between them. Simonetto and Auber [12] described this structure naming it intersection graphs. Their method aims to represent every collection of overlapping sets in a Euler diagram fashion (even when a proper Euler diagram does not exist), and they pointed out how the construction of the intersection graph is the main issue to solve. The authors explained the characteristics that a well formed intersection graph should or must have, but no algorithms have been provided to construct it. In this paper we will present an heuristic algorithm that solves this problem.