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