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