I'm going to give away "a secret" on this one.

I went to the the [Stanford Parser](http://nlp.stanford.edu:8080/parser/index.jsp) and entered the sentence.  I substituted `[` for `(` and `]` for `)` and plugged that into http://yohasebe.com/rsyntaxtree.  That gave a pretty picture.  I usually resize these in something like pixlr to make them smaller.  But now I have the basic Labeled Bracket Notation and the original image I can play with.

The first one I changed to look like this, because it's just how I think of it. 

<pre>
[ROOT
  [S
    [NP [PRP I]]
    [VP [VBP know]
      [NP [PRP it]]
      [PP [IN without]
        [S
          [NP his telling me]
        ]
      ]
    ]
  ]
]
</pre>

Which looks like this:

![enter image description here][2]

In other words, I think of "his telling me" as being something complete, like "his book".

And for the second sentence, I like what the Stanford Parser gives (which is practically identical as what it gave for the first sentence).

<pre>
[ROOT
  [S
    [NP [PRP I]]
    [VP [VBP know]
      [NP [PRP it]]
      [PP [IN without]
        [S
          [NP [PRP him]]
          [VP [VBG telling]
            [NP [PRP me]]]]]]
    ]]
</pre>

And the image is:

![enter image description here][3]

In other words, I think of "him" as somebody doing something.  Without him engaging in telling me.

Someone else can surely give a more grammatical explanation.  Anyone is welcome to raid this answer for the Labeled Bracket Notation contained herein.



  [1]: https://i.sstatic.net/RdCAy.png
  [2]: https://i.sstatic.net/fjs0V.png
  [3]: https://i.sstatic.net/nCU4O.png