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