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