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