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