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