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