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