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