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