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