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