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