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