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