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