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