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