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