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