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