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