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