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