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