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