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