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