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