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