This probably wouldn't help you design a diagram at all, and I am not sure if this is what you meant, but this is how I see it...and some of it is probably pretty weird...
Thinking of hours, minutes, seconds...I am kind of classic, with an old analog style clock in my head that runs on 12hr time. The color changes between white (midnight - noon) & black (noon-midnight). A day is 2 circles that overlap each other.
Weeks are pretty much a straight line, like a typical wall calendar...as are months. When I think of a day in relation to a week or a month, they are pretty much like marking it on a calendar page. They are no longer circles.
A year is circular, moving counter-clockwise, with January at the top, and August at the bottom. (Yes, I know that this is a bit disproportionate but that's how I see it)
The progression of years...
It is a line...moving from left (past) to right (present/future). The time of my birth is at the center, straight in front of me (or slightly to the left of that point). Putting my arms straight out in front of me, the present is in line with my right hand...the future, transparent and off beyond my right hand. The year 1900 sits at my left hand. Everything before that is beyond my left hand.
Each year is a disk on that line, with them overlapping in blocks to represent decades, or centuries, depending on what I am thinking about.
Sometimes I perceive this with color, if it helps to keep things in perspective and separate blocks of time from others.
Visualizing actual events (either from memory or just imagination of the past from before my life)...Everything from 1970 to present is in color...things between 1900 - 1970 are in black & white. Going back in time, everything from about the middle ages to 1900 are in sepia tones...anything before that is in color again. The future is translucent and ghosty.
Do the images in my head move, like video? Only things during my lifetime...everything else is like old photos or paintings.