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)(11,19,22,33)(12,16)(13,18,26,31)(14,17)(15,21)(20,32,35,40)(23,30,37,39)(24,29)(25,28)(27,34)(36,38)(9,11,13,25)(10,15,18,19)(12,20,23,36)(14,22,26,21)(16,27,30,32)(17,28,31,33)(24,35,37,34)(29,38,39,40)(2,5)(6,8)(9,12,14,24)(10,16,17,29)(11,20,22,35)(13,23,26,37)(15,27,28,38)(18,30,31,39)(19,32,33,40)(21,34,25,36)(1,3,4,7)(2,6,5,8)(10,17)(15,28)(16,29)(18,31)(19,33)(27,38)(30,39)(32,40)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.