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)(15,22)(16,17)(18,27)(19,21)(20,25)(23,24)(26,28)(6,9)(7,11)(13,15,18,25,19,26,17,24)(14,20,16,22,21,23,27,28)(2,4)(5,6)(7,10)(8,9)(11,12) involution — undirected(6,9)(10,12)(13,16,19,27)(14,17,21,18)(15,23,26,20)(22,24,28,25)(5,7,8,11)(6,10,9,12)(13,17,19,18)(14,16,21,27)(15,24,26,25)(20,22,23,28)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.