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