There are several others on YouTube. Really you are not so much making cable as dressing them up.
You can find an assortment of TechFlex wire jackets at Parts Express and on Ebay. Ebay
probably has a greater assortment of colors.
Speaker Pants from Parts Express
or very common on Ebay
and possibly Amazon.
Heat Shrink, which is handy, can be purchased just about anywhere. However, Parts Express
(and others) has Heat Shrink in an assortment of colors -
Then simply purchase the wire terminations (Bananas, Spades, Others)
to suit your needs and your budget.
Then it is simply a matter of putting it all together.
Most of the Wire Jacket covers a range of sizes. For example, this is Nominal 1/4", but if you stretch it, it shrinks down to 1/8" and if you compress it, it expands to 7/16". Though stretched it is longer, and compressed it is shorter, so remember this when you order the Wire Jackets to make sure you get the right length.
I think I would order on the smaller size and expand it to fit, that way I'm assured of a reasonably tight fit in the Jacket. For example, this 1/8" nominal, has a range of 3/32" to 1/4".
However, the MOGAMI wire has a considerable diameter of about 0.472". 1/4" will expand to 0.4375", that's 0.035" difference, I think I could make it work.
Or as an alternative, thin covering In-Wall wire of the same 12ga, is only 0.252" in diameter. Which means the 1/8" would be just 0.002" short, but again, I think I could make it work.
Just a few rambling thoughts.