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