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