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