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