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