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