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