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