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