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