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