Colour reversal is always good; if you've painted the troops in the official scheme ? dark blue armour with gold trim and bright red wings ? then the scheme on the online store
Chaos Space Marine Lord ? bright red armour with gold trim and a dark blue cloak ? would be perfect.
For something more subtle, you could try dark blue armour with silver trim and a bright red cloak; the silver won't clash with the lightning bolts on the armour because there isn't enough room to paint any.