Lucifer had different versions, keylengths could be 48, 64 or 128 bits. The blocklength could be 48, 32 or 128 bits.
The Feistel structure was used there for the first time. Horst Feistel was the main designer.
Alan G. Konheim has a nice description in chapter 9 of his book Computer Security and Cryptography, including diagrams, given the many examples available for DES, you should be able to follow what happens in Lucifer. Google books has the beginning of that chapter.
One of the open expositions is in a paper by Smith, later on described by Sorkin.
It looks like DES with simpler round key bit choices and mostly shifts instead of permutations, thus weaker.
You should be good to go on from here.
Horst Feistel, (1973). Cryptography and Computer Privacy". Scientific American, 228(5), May 1973, pp 15–23.
Konheim, Alan G. (2007), Computer Security and Cryptography, John Wiley & Sons, p. 283, ISBN 9780470083970.
- A. Sorkin, (1984). LUCIFER: a cryptographic algorithm. Cryptologia, 8(1), 22–35, 1984.