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