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