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