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