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