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