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