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