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