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