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