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