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