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