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