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