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