Yeah, I think Cell could be looked as a normal SSJ there, but Piccolo in his fight with 17, in the first portion of the fight, also exhibited a similar aura... Yellow-ish when powering up and then that white colored aura. It could be just a representation of some level of power, which could be a possibility too.
It's really tough to distinguish a MSSJ aura from a normal SSJ aura. It'd be nitpicking details, but normal SSJ seems to have less pronounced spikes, with the aura being more tied to the body without spikes popping up much. Goku seemed to have those spikes popping out more when in MSSJ and so did Cell vs him. Vegeta and Trunks vs the Cell Juniors had too, but less intense than Vegeta... Though their aura seemed to have those spikes more pronounced than when Vegeta fought 19 for example.
Though Cell from future Trunks' timeline also showed those more spiked white-colorished aura, similar to MSSJ... While he shouldn't be different from the Cell who almost killed Kamiccolo. So I think there may not even have been an intention for the MSSJ aura to look different from SSJ... More like an artistic expression, I'd say. Maybe Imperfect Cell's aura is indicative of a SSJ like aura or just that he is powered up in comparison to before (aka Ginger Town Cell), much like Kamiccolo also had that kind of aura while pre Kami Piccolo did not. Though in the CGs, since grade 3 and SSJ2 are clear traits that have obvious distinguishable features, I'd say it's more arguable Cell showed 100% SSJ like forms there, while before, possible, but not necessary.