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