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