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