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