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