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