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