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