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