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