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