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