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