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