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