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)(17,24)(18,21)(19,23)(20,26)(27,28) involution — undirected(2,4)(5,6,8,9)(7,10,11,12)(13,15)(14,20)(16,19)(17,27)(18,26)(21,22)(23,28)(24,25)(6,9)(7,11)(14,21)(15,16)(17,18)(20,25)(22,28)(23,24) involution — undirected(5,7)(6,10)(8,11)(9,12)(13,16,19,15)(14,22,23,25)(17,27,18,26)(20,24,28,21)(6,9)(7,11)(14,23)(15,16)(21,24)(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.