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