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