Transition Diagram of a Universal Turing Machine
Here are some references:


Claude Shannon, "A universal Turing machine with two internal states", 1956.
Marvin Minsky, "A 6-symbol 6-state Universal Turing Machine", 1960.
Shigeru Watanabe, "5-Symbol 8-State and 5-Symbol 6-State Universal Turing Machines", 1961.


Also Odifreddi writes ["Classical Recursion Theory", vol I, p. 133]:


  "..., and explicit constructions of universal Turing machines are in Turing
  [1936], Wang [1957a] and in many textbooks, e.g. Hermes [1965], Minsky
  [1967], Arbib [1969], Hopcroft and Ullman [1979]. More information on
  the topic is in Davis [1956], [1957], Shannon [1956], Rogers [1967]
  and Priese [1979]."