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