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