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