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