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