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