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