One vertex per element, one color per generator, with an edge from x to x·s.
(1,2) involution — undirected(4,6)(7,8,12,17,13,18,10,22)(9,14,19,29,21,30,23,37)(11,16,24,32,26,33,25,15)(20,28,35,27,36,38,34,31)(3,4,5,6)(7,9)(8,14)(10,23)(11,20)(12,19)(13,21)(15,31)(16,28)(17,29)(18,30)(22,37)(24,35)(25,34)(26,36)(27,32)(33,38)(7,10,13,12)(8,15,18,32)(9,19,21,23)(11,25,26,24)(14,27,30,31)(16,17,33,22)(20,35,36,34)(28,37,38,29)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.