The color code is showing a "fluence" in units of particles per 10^10 km^2, which of course is particles per unit area. To make sense of this you need motion perpendicular to the area so that km/sec * particles/km^3 = particles/km^2 /sec . Hmmmm. Well a search on "209P fluence" gave me a pdf with this exact figure. How about them apples! The caption to it reads:
Figure 2. The footprint of the meteoroid stream from 209P/LINEAR projected on the ecliptic. The colour scheme labels the free space (no gravitational focusing) fluence of particles through a plane perpendicular to the stream’s arrival direction. Locations of the Earth at particular times are labeled with arrows. The Sun is to the upper right.
Well, Hmmmm again. There's no time unit. But ah, there is! Another search says "fluence" is a "flux integrated over time" ... and the chart is labeled "fluence ... within +/- 7.0 days ... " So that means an integrated flux over 14 days, or an AVERAGE flux of this fluence/14 days. Much of a muchness.
So we're looking at ( for orange ) about 10^8 particles per 10^10 km^2/14 days . Now this is the flux of the stream in the solar frame of reference, ignoring the motion of the earth, which is ( presumably ) assumed to be sampling this flux at a slower speed.
Well, 10^10 km^2 is (10^5 km)^2 or roughly the "footprint" of the earth. So we're talking about 10^8/14 particles/day or 10^8/14/24 ~= 300000 particles per hour entering the earth's atmosphere, at peak.
This is how I see it, but I've been known to be wrong. Anyway, this is my idea of a fun time, so thanks for asking!
These are tiny particles, and you'd have to guess what fraction of them would be observable from a given location. If this is 1/1000 then you'd have 300/hour or 5/minute of those tiny little streaks, assuming a dark sky. This is a lot as meteor showers go, and with a lot of little ones, you're going to see some big ones, so we'll see.