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