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