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