Although the above chromaticity diagram commonly gets thrown around to represent ACES (i.e., as ACES2065-1), we are instructed to not use that color space for rendering, but to instead to use the much smaller ACEScg color space (see the two compared in the first diagram, below) which represents a much smaller color gamut that is closest to Rec. 2020 (see subsequent diagram). We still lose out on a good chunk of the greens, cyans, and blues, as with Rec. 2020. For now, there aren't any devices that can display these colors anyways, but 10-20+ years down the road... Who knows?
Diagram comparing ACES2061-1 and ACEScg on the two common chromaticity diagrams
Diagram comparing ACES2065-1 and ACEScg with other common color gamuts