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