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