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