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