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