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