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)(15,21)(16,25)(17,24)(18,23)(19,20)(22,28)(26,27)(5,7)(6,9)(8,12)(10,11)(13,15,18,20)(14,19,23,21)(16,22,27,24)(17,26,28,25)(6,10)(9,11)(13,16,17,19,18,27,28,21)(14,20,22,25,23,15,24,26)(7,12)(9,11)(13,15)(14,21)(16,22)(17,26)(18,20)(19,23)(24,27)(25,28) involution — undirected(1,3,4,2)(6,10)(9,11)(13,17,18,28)(14,22,23,24)(15,25,20,26)(16,21,27,19)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.