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