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