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