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