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