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