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