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