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