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