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