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