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)(25,26,30,36,31,35,29,34)(27,32,37,33,28,38,39,40)(1,2)(3,7)(4,5)(6,8)(9,11)(10,14)(12,18)(13,19)(15,22)(16,17)(20,23)(21,24)(25,27,31,28)(26,32,35,38)(29,39,30,37)(33,34,40,36)(2,5)(6,7)(25,28,31,27)(26,33,35,40)(29,39,30,37)(32,34,38,36)(9,12,13,21)(10,15,16,20)(11,18,19,24)(14,22,17,23)(25,29,31,30)(26,34,35,36)(27,37,28,39)(32,33,38,40)(1,3,4,8)(2,6,5,7)(11,19)(14,17)(18,24)(22,23)(26,35)(32,38)(33,40)(34,36)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.