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