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