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)(25,26,31,29,30,33,27,34)(28,36,37,38,39,32,35,40)(1,3,4,7)(2,5,6,8)(9,11)(10,14)(12,18)(13,19)(15,21)(16,17)(20,24)(22,23)(25,27,30,31)(26,29,33,34)(28,37,39,35)(32,38,36,40)(2,6)(3,7)(9,12,13,20)(10,15,16,22)(11,18,19,24)(14,21,17,23)(25,28,30,39)(26,32,33,36)(27,35,31,37)(29,40,34,38)(2,6)(5,8)(11,19)(14,17)(18,24)(21,23)(25,29,31,33,30,34,27,26)(28,38,37,32,39,40,35,36)(10,16)(14,17)(15,22)(21,23)(28,39)(32,36)(35,37)(38,40) 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.