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