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