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