Described is a technology for reducing the layout complexity of a graph, e.g., an STT graph. Nodes with similar incoming and outgoing links are grouped as candidate groupings to possibly be clustered. For each candidate grouping, if the nodes in the candidate grouping and/or the candidate grouping meet clustering criteria, the candidate grouping is clustered into a clustered node. The criteria may include user-specified parameters directed towards the nodes and/or the candidate groupings. For example, a node is removed from a group if the number of incoming links thereto or the number of outgoing links therefrom exceed maximum incoming and outgoing parameter values, respectively. A group is only clustered if the number of nodes therein meets a minimum size parameter.