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