One vertex per element, one color per generator, with an edge from x to x·s.
(1,2) involution — undirected(4,6)(8,12)(9,15)(14,19)(16,21)(23,24,29,27)(25,32,26,30)(28,35,36,31)(33,37,34,38)(8,12)(9,15)(10,17)(20,22)(23,25,29,26)(24,30,27,32)(28,33,36,34)(31,37,35,38)(3,4,5,6)(7,8)(9,13)(10,14)(11,12)(15,18)(16,20)(17,19)(21,22)(23,26,29,25)(24,30,27,32)(28,34,36,33)(31,37,35,38)(7,9,11,15)(8,13,12,18)(10,16,17,21)(14,20,19,22)(23,27,29,24)(25,30,26,32)(28,35,36,31)(33,37,34,38)(7,10)(8,14)(9,16)(11,17)(12,19)(13,20)(15,21)(18,22)(23,28,29,36)(24,31,27,35)(25,33,26,34)(30,37,32,38)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.