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