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