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