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