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