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