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