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