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