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