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