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