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