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