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