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