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)(13,14,16,17)(15,19,20,18)(21,22,24,26)(23,27,28,25)(6,7)(10,11)(14,17)(15,20)(21,22,24,26)(23,27,28,25)(8,12)(10,11)(14,17)(18,19)(21,22)(23,25)(24,26)(27,28) involution — undirected(1,2)(3,4)(5,7,9,6)(8,10,12,11)(13,15,16,20)(14,18,17,19)(5,8,9,12)(6,10,7,11)(13,14)(15,19)(16,17)(18,20)(21,23,24,28)(22,25,26,27)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.