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