As of Version 10, most of the functionality of the Combinatorica package is built into the Wolfram System. >>

constructs an edge list representation from a list of ordered pairs l, using a circular embedding.

uses v as the embedding for the resulting graph. The option Type that takes on values Undirected or Directed can be used to affect the kind of graph produced. The default value of Type is Directed. Type->Undirected results in the underlying undirected graph.