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