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