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