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