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)(13,14)(15,23)(16,22)(17,20)(18,21)(19,25)(24,27)(26,28) involution — undirected(1,2,3,4)(7,8)(10,11)(13,14)(15,24)(16,20)(17,22)(18,21)(19,26)(23,27)(25,28)(5,7,9,8)(6,10,12,11)(13,15)(14,19)(16,25)(17,27)(18,26)(20,23)(21,24)(22,28)(5,8,9,7)(6,11,12,10)(13,16,18,17)(14,20,21,22)(15,25,26,27)(19,23,24,28)(6,12)(10,11)(14,21)(19,24)(20,22)(23,28) involution — undirectedA 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.