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