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