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