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