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