You don't really need the icons. To select, just remember the F1, F2, etc.
F1 - Release Rate Up
F2 - Release Rate Down
F3 - Climber
F4 - Floater
F5 - Bomber
F6 - Blocker
F7 - Builder
F8 - Basher
F9 - Miner
F10 - Digger
F11 - Pause
F12 - Nuke (you have to press it twice quickly)
Just press those keys to select.