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