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)(11,19)(12,23,25,16)(13,17)(14,28)(15,21)(18,27)(20,33,36,29)(22,30)(24,31,39,37)(26,32,40,38)(34,35)(2,5)(6,7)(9,11)(10,15)(12,24,25,39)(13,21)(14,22)(16,31,23,37)(17,19)(18,30)(20,26,36,40)(27,35)(28,34)(29,32,33,38)(9,12,14,26,13,25,27,40)(10,16,28,38,17,23,18,32)(11,20,35,39,21,36,22,24)(15,29,30,31,19,33,34,37)(1,3,4,8)(2,6,5,7)(10,17)(15,19)(16,23)(18,28)(29,33)(30,34)(31,37)(32,38)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.