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