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