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