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