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