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)(11,21)(12,13)(14,19)(15,33)(16,24)(17,28)(18,31)(20,32)(22,39)(23,26)(25,36)(27,30)(29,40)(34,38)(35,37) involution — undirected(2,5)(6,8)(9,11,14,24)(10,16,19,21)(12,26,27,40)(13,29,30,23)(15,34,32,25)(17,37,31,39)(18,35,28,22)(20,38,33,36)(1,3,4,7)(2,6,5,8)(9,12,15,28,14,27,32,18)(10,17,20,13,19,31,33,30)(11,22,25,26,24,35,34,40)(16,29,36,37,21,23,38,39)(9,13,15,31,14,30,32,17)(10,18,20,12,19,28,33,27)(11,23,25,39,24,29,34,37)(16,35,36,40,21,22,38,26)(2,5)(6,8)(10,19)(12,27)(16,21)(18,28)(20,33)(22,35)(26,40)(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.