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