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