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