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