I found a Reddit thread talking about how to wire these up, and it included this picture.
[image|3320258]
If yours follows the same layout, then it would correspond to the following connections.
1.25uF Red
1uF Purple
1.5uF Brown
Ground Grey / Grey
So the two grey wires are both grounds, and you can use one or both of them. Each of the three capacitors should be wired between the given colored wire and a ground. So if you buy three separate capacitors, you'd wire them to wherever the existing wires go as follows.
1.25uF Red to Grey
1uF Purple to Grey
1.5uF Brown to Grey
I ran across an eBay listing that's as close as anything I could find; it has two out of the three values you need.
[link|https://www.ebay.com/itm/372117775919|CBB61 1.5UF+1UF+2UF 450 V AC Small Generator Capacitor 50/60Hz - eBay|new_window=true]
[image|3320268]
This one is really scrambled according to the colors. Here's how you'd wire it
1.5uF Red to existing Brown
1uF Brown to existing Purple
Gray to Gray / Gray to Gray
Then you'd still need a separate 1.25 to go to the existing Red / Grey connections.
Sheesh, be nice if this stuff had some kind of standardization, right?