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