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