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