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