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