Okay, here's what I hacked up in HomeStyler while I was having my coffee.
The floorplan:
It's rough and somehow doesn't match up with my measurements. Part of that is the thickness of the walls which I can't be bothered to estimate, but there's a whole foot of extra space near the entrance that I had to add to make the sapce square like it is in the real world... but the discrepancies are near the closet and the entrance, they don't particularly play into the space of the office itself. The windows aren't placed very accurately, but they aren't 1:1 representations of the windows in the place anyways.
This isn't a very fair comparison, the only 'white' color for walls they had was this paper white and a very distinctly 'cream' off-white... at least on my monitors. There's a bit of warmth to the white on my walls, it seems like the same white paint was used on the walls, the crown molding at the roof and the DIY molding along the floor that looks like it was mostly made with spare pressure-treated lumber, 1"x4" or something. The 'wood' floor is actually pretty true to what the landlords put in here and that weird ceiling tiling was the closest to what I could get in here.
First off! Getting a black desk is a meh choice (not bad, not stellar), wouldn't recommend it with the red or rustic brick wallpaper in stock config, the marble wrap would make it a lot more acceptable with the rustic brick, and would work wonders to extend the life span of the desk top.
(I recommend the gray brick wallpaper for better contrast with the floor, depth, ease of application, lightness, theme... add more colour with personality, like artwork some accessories, tools even)
As far as the camouflage the black would offer, it comes at the cost of making the whole area around you feel more cramped, possibly less efficient. Marble wrap negates some of that.
The bar between the legs would be awesome for managing the cables though!
Had it not been for the fact that it isn't moving with your top, so getting a cable tray and attaching it to your top would be how you should manage the majority of your cables, make sure to bundle and keep them tidy so it won't be a mess you can notice directly in the foreground. Ideally you'd only want a power cable coming down at the back of one of the legs, I'd suggest anchoring that cable down close to the corners of the desk top and leg, giving it slack right at the corners for a very clean look
How phased are you be by the windows, light and sound reflections, sunlight, artificial light... power outlet position, curtains, blinds, did you have a spot in mind for your desk and perhaps other furniture, any side of your personality you'd like to display there?
What and how would you place things on your desk for your production, your work..
The room actually has a lot of potential, and for anyone who'd feel totally overwhelmed on how to make a setup efficient, inspiring... attractive, you wouldn't be alone because it is an overwhelming achievement as opposed to a simple setup.