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)(27,29)(28,35)(30,31)(32,38)(33,39)(34,37)(36,40)(1,2,4,6)(3,5,8,7)(11,15)(14,16)(17,19,22,21)(18,23,20,24)(26,31)(29,39)(32,35)(37,40)(1,2)(3,5)(4,6)(7,8)(9,10,13,12)(11,14,15,16)(17,19,22,21)(18,24,20,23)(25,27,30,33)(26,29,31,39)(28,36,38,34)(32,37,35,40)(1,2)(3,5)(4,6)(7,8)(9,11,13,15)(10,14,12,16)(17,20,22,18)(19,23,21,24)(25,28,30,38)(26,32,31,35)(27,34,33,36)(29,40,39,37)(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)(26,33)(27,31)(28,37)(30,39)(32,34)(35,36)(38,40)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.