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