Here is my code.
g = Import["http://mat.gsia.cmu.edu/COLOR/instances/homer.col", "DIMACS"]; MinimumVertexColoring[g]
O/p is
MinimumVertexColoring[ "The whole graph is displayed here"]
Please let me know. I have just started using Mathematica
MinimumVertexColoring is a Combinatorica function available in the Combinatorica package. To use it, you will need to
The default kind of Graph in Mathematica is a different object than the combinatorica graph. So the function won't know what to do with the graph unless it's a combinatorica graph.