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