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