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