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