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