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