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