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