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)(15,25,27,28)(16,22,20,21)(17,23,18,26)(5,7)(6,9)(8,11)(10,12)(13,15,18,22,19,27,17,21)(14,20,23,25,24,16,26,28)(2,4)(7,11)(9,12)(13,16)(14,21)(15,23)(17,25)(18,28)(19,20)(22,24)(26,27) involution — undirected(5,7)(6,9)(8,11)(10,12)(13,16)(14,22)(15,26)(17,25)(18,28)(19,20)(21,24)(23,27) involution — undirected(7,11)(9,12)(13,17,19,18)(14,23,24,26)(15,21,27,22)(16,28,20,25)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.