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