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