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