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