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