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