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