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