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