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