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