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)(15,23)(16,20)(17,19)(18,27)(21,25)(22,26)(24,28) involution — undirected(1,2,4,3)(5,6)(7,10)(8,9)(11,12)(14,19)(15,24)(16,25)(18,26)(20,23)(21,28)(6,9)(10,11)(13,15,18,16,17,25,26,24)(14,20,22,23,19,28,27,21)(5,7,8,12)(6,10,9,11)(13,16,26,15,17,24,18,25)(14,21,27,28,19,23,22,20)(1,3,4,2)(14,19)(20,28)(21,23)(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.