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