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