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