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