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