i've looked in transport.cpp = no color options for buttons.
Overall the grey around the buttons could be darker to increase contrast.
'AC' to be pastel something - (don't care -dont use it! )
'Click' to be pastel green when engaged.
'Sync' to be pastel blue when engaged.
'Record' to be pastel red/flashing when enabled - bright red/constant
when rolling - as is when disengaged.
'Jack" to be a pastel yellow when engaged
'Master" to be a pastel orange when engaed.
the punch in/out & loop can all be a pastel green or blue i reckon.
let me know what to do and i'll attempt it if you like ..