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