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