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