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