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