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)(11,17,19,14)(12,20,21,15)(18,22,24,23)(25,26,30,31)(27,32,33,28)(29,34,38,39)(35,37,40,36)(9,11)(10,14)(12,18)(13,19)(15,22)(16,17)(20,23)(21,24)(25,27,30,33)(26,32,31,28)(29,37,38,36)(34,40,39,35)(2,5)(6,8)(25,28,31,27,30,32,26,33)(29,37,39,40,38,36,34,35)(9,12,13,21)(10,15,16,20)(11,18,19,24)(14,22,17,23)(29,38)(34,39)(35,40)(36,37)(1,3,4,7)(2,6,5,8)(11,19)(14,17)(18,24)(22,23)(25,29,26,34,30,38,31,39)(27,35,28,36,33,40,32,37)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.