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