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