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