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