I don't think there is any way to actually "see" the sketches because we didn't put any in the game, but for talking about it with Ogata:
[Spoilers for the game below]-----------------------------------
.
.
.
.
.
You need to pick up the book at the farmer's market and then take it back to your apartment to look through. Once you have looked through all the pages, you will know that Vasily draws Ogata. Then later in Ogata's route, you can mention it for romance points when talking about Vasily.
Note that you will need to actually meet Vasily in order to be able to talk about him with Ogata, so after looking through the book, make sure to go back to the farmer's market and give it to Vasily or call Vasily to give it back to him at his apartment.
Hope this helps, and sorry to disappoint about the sketches themselves not existing...