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