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