tl;dr You can know how to dodge well in advance by only looking at the boss' starting position

There will always be the same orientation of colors relative to the boss for each cardinal/ordinal the boss jumps to after it casts Diabolic Gate. If the boss jumps N, for example, the gates starting clockwise from the boss will be yellow, blue, red, green, red, yellow, green.

(Directions here are relative to the boss)
Left Diagonal - Line AoE through NW/SE
Right Diagonal - Line AoE through NE/SW
Middle - Line AoE through E/W

I've seen 6 starting points:

N - YBRGRYG = LD - RD - Mid
E - GYRBRBY = Mid - LD - RD
S - RBBYGYR = Mid - LD - RD
SW - GBBRRYG = RD - LD - Mid
W - GRRGYBY = RD - LD - Mid
NW - BBRRGYG = LD - RD - Mid

How you choose to dodge the patterns is up to you. If I see anything but W/SW, I start east of the boss, move in after the first charge, wait for the opposite diagonal to go off (in this case LD) and then move to where the LD hit. For W/SW, I can either move into the LD section to start, or I can start from the west if I want to be extra safe.