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