One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(9,10)(11,20)(12,23)(13,18)(14,29)(15,16)(17,26)(19,24)(21,35)(22,34)(25,38)(27,37)(28,31)(30,39)(32,40)(33,36) involution — undirected(1,2,4,3)(5,6)(7,8)(9,11,13,15)(10,16,18,20)(12,21,25,27)(14,22,28,24)(17,30,32,33)(19,31,34,29)(23,37,38,35)(26,36,40,39)(6,8)(9,12,24,39,15,27,28,40,13,25,22,36,11,21,14,26)(10,17,29,35,20,33,34,38,18,32,31,37,16,30,19,23)(1,3,4,2)(10,18)(16,20)(17,32)(19,34)(23,38)(29,31)(30,33)(35,37)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.