Have I invented a new data structure?
I've never seen this data structure before.  However, it doesn't seem like a good choice for storing a set of words, for most purposes.  I see three significant disadvantages:


Performance. Looking up a word in this data structure can potentially be quite slow.  In particular, when looking up a word of length $n$, checking whether it contains a particular letter involves looking at all $n$ characters of the word.  Therefore, traversing the entire tree (all 26 levels) might require reading the entire word 26 times.  In contrast, a trie reads each character of the word only once, so might be about 26x times faster.  Same for a hashtable.
Space usage. This might take a lot of space.  I am assuming you won't construct a node unless it is needed (i.e., if it has only one child, you'll omit the node).  With that optimization, the depth of the tree is at most 26 if you're using words with letters a-z.  If you are storing strings in Unicode, the depth of the tree might be enormous, and in the worst case this might devolve to a data structure where the depth of the tree is proportional to the number of words in the set, and then the space usage is bad and the time for a lookup is very bad (linear in the size of the set).  Without that optimization, the number of the nodes in the tree can be as large as $2^{26}$ for letters a-z, or enormous for Unicode strings. 
Incomplete. This isn't a complete data structure.  It cannot distinguish between two words with the same set of letters, e.g., between words that are permutations of each other (anagrams).  Therefore, you'll need another data structure for storing the second-level sets (your circle shapes).  If we had a good data structure for that purpose, why wouldn't we use it for all the words, and skip your data structure?  Conversely, if you use a poor data structure for that, then your data structure inherits the limitations of that data structure: for instance, if you store all the words in the circle in a linked list, then lookups will be slow as they might need to traverse the entire list.