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