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