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