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