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