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