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