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