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