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