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