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