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