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