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