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