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