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