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