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