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