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