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