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