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