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