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