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