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