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