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