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