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