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