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