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