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