According to her SimDNA in SimPE, she had blonde hair before it turned grey. Though all deceased ancestors of Loki and Erin Beaker have brown eyes in their thumbnails, only Grainne and Gertrude Beaker actually have them. This can be proven by viewing their SimDNAs. However unlike Gertrude, Grainne would have brown eyes in her headshot, even if she didn't have them when resurrected. The reason for this is because she has a corrupted face. According to Grainne's age data, she had 17 days left before dying of old age, which hints that she had access to Elixir of Life at some point in her life.