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)(13,14,18,22,17,21,15,19)(16,24,23,20,26,27,25,28)(1,2)(3,4)(5,6)(7,11)(8,10)(9,12)(13,15,17,18)(14,19,21,22)(16,25,26,23)(20,24,28,27)(5,7,8,12)(6,9,10,11)(13,16)(14,20)(15,23)(17,26)(18,25)(19,27)(21,28)(22,24)(2,4)(7,12)(9,11)(14,21)(16,26)(19,22)(23,25) involution — undirected(6,10)(9,11)(13,15,17,18)(14,22,21,19)(16,23,26,25)(20,24,28,27)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.