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