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)(11,15)(12,13)(14,16)(18,21)(22,24)(25,26,30,28)(27,32,35,31)(29,33,37,36)(34,39,40,38)(3,7)(6,8)(9,10)(11,15)(12,13)(14,16)(19,23)(22,24)(25,27,30,35)(26,31,28,32)(29,34,37,40)(33,38,36,39)(2,5)(6,8)(10,13)(14,15)(17,18,20,21)(19,22,23,24)(25,27)(26,32)(28,31)(29,34)(30,35)(33,39)(36,38)(37,40)(1,2)(3,6)(4,5)(7,8)(9,10)(11,14)(12,13)(15,16)(17,18)(19,22)(20,21)(23,24)(25,28,30,26)(27,32,35,31)(29,33,37,36)(34,38,40,39)(1,3,4,7)(2,6,5,8)(9,11,12,16)(10,14,13,15)(17,19,20,23)(18,22,21,24)(25,29)(26,33)(27,34)(28,36)(30,37)(31,38)(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.