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