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