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