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