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