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