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