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