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