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