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