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