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