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