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