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