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