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