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