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