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