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