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