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