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