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