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