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)(13,14,18,22)(15,19,23,24)(16,25,27,20)(17,21,26,28)(5,7)(6,9)(8,12)(10,11)(13,15)(14,19)(16,26)(17,27)(18,23)(20,21)(22,24)(25,28) involution — undirected(1,2,3,4)(13,16,14,20,18,27,22,25)(15,21,24,26,23,28,19,17)(6,10)(9,11)(13,14,18,22)(15,19,23,24)(16,20,27,25)(17,28,26,21)(7,12)(9,11)(13,17,22,28,18,26,14,21)(15,20,19,16,23,25,24,27)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.