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)(15,20)(16,26)(17,23)(18,21)(19,24)(22,27)(25,28) involution — undirected(1,2,4,3)(5,7)(6,9)(8,11)(10,12)(13,15)(14,20)(16,17)(18,25)(19,27)(21,28)(22,24)(23,26)(6,10)(7,11)(14,21)(15,25)(16,27)(23,24) involution — undirected(6,10)(9,12)(13,16,17,15,18,27,19,25)(14,22,23,28,21,26,24,20)(1,3,4,2)(13,17,18,19)(14,23,21,24)(15,16,25,27)(20,26,28,22)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.