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