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