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