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