There are "computer moves" which stand out vs human players. These normally show up in lines where there are many options of roughly equal value and the computer picks a move that is infinitesimally better but out of 'theme' with the position.
They can also show up when for instance there are multiple checkmates in a position. The computer will choose the one requiring the least number of moves even if it requires deep calculation and perfect play. Humans will just trade off material and go for an easy win.
Now that chess engines have started to use neural networks in move selection the amount of "computer moves" has decreased noticeably.
> if you were a top player and looking at the moves of an opponent, could you discern if the style was more similar to a top rated human or a top rated computer?
With a large enough sample size I believe that top players would be able to tell the difference. But that sample size is much larger than a single game or likely even the ~10 games being played in a tournament.
Edit:
Oh I should also mention that in the context of cheating with computers there are more signals to look at than the moves themselves. Time management is normally a huge giveaway for cheating. In online chess this normally manifests itself as players using the exact same amount of time for each move in spite of the positions being very different in terms of complexity.
In the match being talked about above Hans, the challenger, used a suspicious amount of time during the opening sequence. He played the opening moves in around 10 minutes which is weird because if he had memorized the lines he would have played them much faster. If he didn't memorize the lines then it would have taken him much more than 10 minutes to calculate it all.