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