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