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