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