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