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