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