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)(13,14,18,19)(15,20,26,23)(16,21,22,17)(24,28,25,27)(5,7)(6,9)(8,12)(10,11)(13,15,18,26)(14,20,19,23)(16,24,22,25)(17,27,21,28)(2,4)(14,19)(15,23)(16,22)(20,26)(24,28)(25,27) involution — undirected(6,10)(9,11)(13,16)(14,21)(15,24)(17,19)(18,22)(20,28)(23,27)(25,26) involution — undirected(7,12)(9,11)(13,17,18,21)(14,22,19,16)(15,25,26,24)(20,28,23,27)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.