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