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