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