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)(13,14,17,16)(15,19,20,18)(21,22,27,26)(23,24,25,28)(6,10)(8,11)(14,16)(18,19)(21,23,27,25)(22,28,26,24)(13,15)(14,18)(16,19)(17,20)(21,24)(22,25)(23,26)(27,28) involution — undirected(1,2)(3,4)(5,7,9,12)(6,11,10,8)(13,15)(14,18)(16,19)(17,20)(21,25,27,23)(22,28,26,24)(5,8,9,11)(6,12,10,7)(13,16,17,14)(15,19,20,18)(21,26,27,22)(23,28,25,24)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.