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