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