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