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