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