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