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