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