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