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