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