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