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