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