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